Elevator system

ABSTRACT

A new and improved elevator system, and method of allocating calls and assigning cars in an elevator system to serve calls for elevator service. When a floor call is received, it is processed by adding it to the assignment register of at least one of the elevator cars, or by creating a demand signal relative to the call. The floor calls in the system are reprocessed in response to certain conditions, to determine if there is a closer suitable car to each of the floor calls than the car which presently has the call in its assignment register. When a closer suitable car is found the call is added to the assignment register of this closer car, and it is removed from any other assignment register in which it appears.

ite States atent 1 [111 3,851,733

Sackin et al. Dec. 3, 1974 ELEVATOR SYSTEM Primary Examiner-Robert K.Schaefer [75] Inventors: Milton Sackin, Pittsburgh; David M. AssistantExaminer w' Duncanson Edison, Murrysvine, both of Pa. Attorney, Agent,or Firm-D. R. Lackey [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh Pa, [57] ABSTRACT A new and improved elevator system, andmethod of [22] Flled' 1973 allocating calls and assigning cars in anelevator sys- [21] Appl. No.: 340,617 tern to serve calls for elevatorservice. When a floor call is received, it is processed by adding it tothe assignment register of at least one of the elevator cars, or byCreating a demand Signal relative to the can The [58] Field 187/29 floorcalls in the system are reprocessed in response to certain conditions,to determine if there is a closer [56] References Cited suitable car toeach of the floor calls than the car which presently has the call in itsassignment register.

UNITED STATES PATENTS When a closer suitable car is found the call isadded to 3,443,668 '5/1969 Hall et a1, 187/29 the assignment register ofthis closer car, and it is re- L 5/1970 DC Lamutcrm 187/29 moved fromany other assignment register in which it 3,587,786 6/1971 Savino 187/29appears.

3 589,473 6/197] Kirsch et al 187/29.

30 Claims, 30 Drawing Figures INTERFACE TIMING umrr cm CALL F CONTROL'ER To DOOR FLOOR HALL SELECTOR LANTERNS DOOR OPERATOR 54 I DISTANCE 49!I -PULSES Isl LANDING PULSE A '3 v DETECTOR 6 1Q H PULSE I [DETECTORIPATENTEL DEE 74 SHEET 01 or .18

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ASGN MODE =00 f ASGN MID BLDG PARK AVADASGN 339 337 335 SET CAR N v SETCAR DTPK DNPK 34o F 342 343 I OUTPUT UPDATE UPDATE H W61 BTRA WORD INPUTDATA PATTNTT', IITI 3mm SHEET 1'3 BF Ia INITIALIZE FOR UP CALLS LDA WITHCALL WORD INITI ALIZE FOR DOWN CALLS FINISHED WITH IITH BIT OF?YCALL SETBIT IN XOR YCALL+ CLR WOR 8T STORE IN CCLR CLR YCALL YCALL O I CALLSADDCALL To I TABLE ,S ZONE 6 TIMER NCL REMOVE CALL AND COMPACT TABLEDECR NCLTYNCLO REM VE BIT FROM CRA FOR EACH cAR WITH PROPER SASS FIG.2|-

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DEMINDIMZ PROGRAM DEMIND BSMT DEMIND 2L0 DEMIND HI PROGRAM PROGRAMPROGRAM FIND EST CAR FOUND vI OUTPUT ASSGMNT SET DEMAS; MF RESET LOBMZDCROSS-REFERENCE TO RELATED APPLICATIONS Certain of the apparatusdisclosed and described in this application, but not claimed, may beclaimed in the following concurrently filed applications:

Application Ser.. No. 340,619, filed Mar. 12, 1973 in the name of .l.Vine, which is assigned to the same assignee as the present application.

Application Ser. No. 340,615, filed Mar. 12, 1973 in the name of N.Sackin, which is assigned to the same assignee as the presentapplication.

BACKGROUND OF THE INVENTION 1. Field of the Invention:-

The invention relates in general to elevator systems and morespecifically to elevator systems in which a plurality of elevator carsare controlled by a central dispatching control apparatus.

2. Description of the Prior Art:

ln the average multi-tenant building which includes an elevator systemhaving a plurality of cars for serving the floors of the building, about80 percent of the floor calls registered above the main floor are downcalls, and even in a single-tenant building down calls predominate.Therefore, elevator systems which include a central dispatcher or systemprocessor for controlling the dispatching of a plurality of elevatorcars in response to floor calls, include special strategy for downcalls.

For example, in one prior art system, the floors are divided into zoneshaving one or more floors per zone, and a down floor call is assigned toall elevator cars having a position, service and travel direction whichis suitable for the call location. The number of zones registering downcalls are counted, and the number of elevator cars set for down travelwhich are in the process of serving down floor calls are also counted.When the number of zones having down calls exceeds the number of downruning cars serving the zones, a demand is created to which available ornon-busy cars are assigned. When there are more down running cars thanzones having down calls, the calls are deleted from the lowest of thecars and this car is made available. Any floor calls which it may havein its assignment register are givento the other cars. I

SUMMARY OF THE lNVENTlON Briefly, the present invention is a new andimproved elevator system, and method of dispatching cars to serve floorcalls for an elevator system, which provides new and improved strategyfor allocating floor calls, and assigning cars to floor calls, includingan improved arrangement and method for handling down calls.

A new floor call is allocated to the assignment register of at least onesuitably conditioned car which is already in the process of servingcalls. A suitably conditioned car is one which is located relative tothe call, and with a travel and service direction such that it will beable to service the call in question as it continues its present coursethrough the building. Failing to find such a car, a demand signal iscreated relative to the call and a non-busy car, i.e., a car which is inservice but which is not presently in the process of serving a call forelevator service, is assigned to the demand call.

If there are no such cars available, the demand persists until a carbecomes available, or a running car finally gets into a position whichconditions it to serve the call.

The processed floor calls are reprocessed when an event occurs whichindicates the possible need to reallocate oneor more of the floor calls.When a floor call is reprocessed, it is determined if there is a closersuitable car to the call floor than the car, or cars which presentlyhave the call in their associated assignment registers. The cars aresuccessively compared relative to a specific call and each time a closersuitable car is found than a previous suitable car, the call is deletedfrom the assignment register of a less suitable car. When all cars havebeen compared, the call is added to the assignment register of theclosest suitable car found. Thus, after reprocessing, only one car hasany one floor call in its assignment register.

When down floor car is allocated to a down running car, this car is notconsidered for further down calls. Thus, placing each call in theassignment register of only one car, and by allowing one down call to beallocated to a down running car, any excess calls over down running carsautomatically creates a demand signal for an available car for each callin excess of the down running cars. It is not necessary to count thecalls and to count the cars to implement this down availabilitystrategy.

Further, the invention results in the call registers of the carsaccurately representing the present traffic condition. The assignmentregisters of the cars are not cluttered with calls which they may notanswer because another closer car with the same call will reach the callfloor first. The invention thus returns the elevator cars to theavailable status much quicker, preventing unnecessary running through thbuilding by cars which will not serve the call they are running for. Thequicker return to the available status also reduces the waiting timerequired to assign available cars to demand calls.

The invention eliminates the prior art problem of deciding which car toremove from running status and to make available when the number of downrunning cars exceeds the number of down calls. In the prior art,arbitrarily deleting the calls from the assignment register of thelowest car and reallocating these calls to the remaining running carsmay not always be the best strategy. With the present invention, thebest strategy is always implemented, as the closest car to a call alwayshas the call assignment.

In one embodiment of the invention, the removal of a floor call from theassignment register of a car which is not as close to the call floor asanother car, is subject to the condition that the less suitable car hasno registered car calls. 1f the less suitable car has one or more carcalls, removing the floor call from its assignment register will nothasten its return to availability status, as the car will continue to bea busy car until it has served its car call. Thus, the floor call is notdeleted from the assignment register of a car which has a car call,since it is a suitably conditioned car for the floor call, and thechance is present that the closer car may for some reason be delayed,allowing the less suitable car to answer the call. Thus, the lesssuitable car retains the floor call in its assignment register until thecloser car answers the call, or the car call is served, or the lesssuitable car answers the floor call.

1. A method of allocating floor calls from a plurality of floors of astructure to a plurality of elevator cars mounted in the structure toserve the floors, comprising the steps of: providing means forregistering floor calls from the plurality of floors of the structure,providing assignment means for each of the elevator cars, processing anew floor call by adding the call to the assignment means of at leastone of the elevator cars or by creating a demand signal, reprocessingeach floor call to locate the closest car in position to serve the call,deleting a floor call added to the assignment means of a car during theprocessing step when the reprocessing step finds a different car whichis closer to the call floor, and adding the floor call to the assignmentmeans of this closer car.
 2. The method of claim 1, wherein the step ofprocessing a new call includes the step of adding each new call to theassignment means of a suitable car whose advanced car position is closerto the call floor.
 3. The method of claim 1 wherein the step ofreprocessing each floor call includes the steps of providing signalsrelative to the advanced car position and service direction of each ofthe elevator cars, and considering these signals to determine if a caris suitable to answer the call.
 4. The method of claim 1 including thestep of providing a reallocation signal responsive to at least oneevent, the existence of which indicates the possible need forreallocating floor calls, with the reprocessing step being initiated inresponse to said reallocation signal.
 5. The method of claim 1 includingthe step of dividing the structure into different zones for up and downcalls and determining the zone of each car depending upon its positionand service direction, and wherein the step of reprocessing each callincludes a step of comparing the zone of a floor call and the zone ofeach car.
 6. The method of claim 1 including the step of providing meansin each elevator car for passengers to register car calls, and whereinthe step of deleting a floor call from the assignment means of anelevator car when a closer suitable car is found is subject to thecondition that the car has no registered car calls.
 7. The method ofclaim 1 including the step of providing a signal when a down floor callis added to the assignment means of an elevator car, and consideringthis signal during the processing and reprocessing steps to remove thiscar from consideration for another down floor call.
 8. The method ofclaim 1 wherein the processing and reprocessing steps consider thoseelevator cars which are not in the process of serving a call forelevator service as not suitable for allocation of calls, and includingthe step of assigning elevator cars in this category to floor calls forwhich a demand signal was created by the processing step.
 9. An elevatorsystem for a structure having a plurality of vertically spaced floors,comprising: a plurality of elevator cars, means mounting the elevatorcars for movement relative to the structure to serve the floors, downfloor call registering means operable for registering a call forelevator service in the down direction from each of a plurality of saidfloors, up floor call registering means operable for registering a callfor elevator service in the up direction from each of a plurality ofsaid floors, car call registering means for each of The elevator carsoperable for registering a call for each of a plurality of said floorswhich may be desired by load in the associated elevator car, dispatchingmeans for allocating registered floor calls to selected elevator cars,and assignment register means associated with each of said elevator carsoperable to receive floor call allocations of said dispatching means,said dispatching means including: collecting means for collecting floorcalls from said up and down floor call registering means, processingmeans for periodically processing certain floor calls collected by saidcollecting means by either adding a selected floor call to theassignment register of at least one elevator car or registering a demandsignal relative to the call, control means for detecting the possibleneed to reallocate at least certain of the floor calls to a differentelevator car than the original allocation, and providing a signal whensuch need is detected, processing means processing only new floor callsunitl said control means provides a signal, at which time all of thefloor calls in the system are processed, said processing means, whenprocessing a floor call previously allocated to an elevator car,allocating the floor call to a second car in response to predeterminedconditions, and deleting the floor call allocation from the assignmentregister of the first car in response to a predetermined condition. 10.The elevator system of claim 9 wherein the control means is responsiveto predetermined conditions the occurrence of any one of which indicatesa possible need to reallocate at least certain of the floor calls, withthe control means being in a first condition, in the absence of all ofthe predetermined conditions and in a second condition when any one ofthe predetermined conditions occur, wherein the processing means isresponsive to the control means to process all of the floor calls whenthe control means is in its second condition, and processing only newfloor calls when the control means is in its first condition.
 11. Theelevator system of claim 10 wherein the predetermined conditions towhich the control means is responsive includes an elevator car bypassingfloor calls and an in-service elevator car going out of service.
 12. Theelevator system of claim 9 wherein the predetermined conditions to whichthe processing means will allocate a floor call previously allocated toa first car to a second car includes the second car being locatedrelative to the call floor and with a service direction consistent withthe service direction of the call, and with an advanced car positionwhich is closer to the call floor than the advanced car position of thefirst car.
 13. The elevator system of claim 9 wherein the predeterminedcondition which will cause the processing means to delete a callallocation from the assignment register means of a first car afterallocating the floor call to a second car is the absence of a car callin the car call registering means of the first car.
 14. The elevatorsystem of claim 9 wherein the processing means includes means forexcluding cars not in the process of serving a call for elevator servicefrom consideration when allocating floor calls, and including means forassigning cars in this category to floor calls for which a demand signalwas registered by the processing means, and wherein said processingmeans compares each car having an advanced car position and servicedirection suitable to answer a specific call with a previous car foundsuitable to determine which car has an advanced car position closer tothe floor of the call, and uses the closer of the two for any subsequentcomparison to obtain the closest suitable car to the call floor when allcars have been considered, with the processing means allocating the callto the assignment register means of the closest suitable car.
 15. Theelevator system of claim 9 including means for excluding an elevator carfrom consideration aS being suitable for a down floor call, when italready has another down floor call in its assignment register means.16. A method of allocating floor calls from a plurality of floors of astructure to a plurality of elevator cars mounted in the structure toserve the floors, comprising the steps of: providing call table means towhich new floor calls are added and answered floor calls are deleted,periodically ordering all of the floor calls in the call table meanssuch that floor calls appear in the call table in the order in whichtheir associated floors are located in the structure, adding callsreceived between ordering steps to an end of the ordered floor calls,providing an assignment register for each of the elevator cars,periodically processing the new calls located at the end of the orderedfloor calls in the call table means by adding each new call to theassignment register of at least one of the elevator cars, or by creatinga demand signal, processing all of the calls in the call table meansfollowing each ordering step by successively determining the suitabilityof at least certain of the elevator cars relative to serving each floorcall, starting with the call located at one end of the call table,determining the suitable car, if any, whose advanced car position isclosest to each floor call by comparing the advanced car position ofeach car found to be suitable for a specific floor call with theadvanced car position of a previous car found to be suitable for thiscall and using only the closer of the two cars for comparison with theadvanced car position of a subsequent car found to be suitable for thiscall, deleting a floor call allocation, if any, from the assignmentregister of a suitable car when a closer suitable car is found for thisfloor call, allocating each floor call to the closest suitable car foundby entering the floor call in the assignment register of the selectedcar, and creating a demand signal when a suitable car cannot be foundfor a floor call.
 17. The method of claim 16 wherein the step ofperiodically processing the new calls located at the end of orderedcalls in the call table means includes the step of allocating each newcall to a suitable car whose advanced car position is closest to thecall.
 18. The method of claim 16 wherein the step of successivelyconsidering the suitability of each car relative to serving each callincludes the steps of providing signals relative to the advanced carposition and service direction of each of the elevator cars, andconsidering these signals to determine if the car is conditioned toanswer the call.
 19. The method of claim 16 including the step ofproviding a reordering signal responsive to at least one event, theexistence of which indicates the possible need for reallocating floorcalls, wherein the presence or absence of the reordering signal is usedto initiate the step of periodic ordering of the floor calls in the calltable, and the step of periodic processing of only the new calls,respectively.
 20. The method of claim 16 including the step of dividingthe structure into different zones for up calls and different zones fordown calls, and determining the zone of each car depending upon itsposition and service direction, and wherein the step of successivelyconsidering the suitability of each car relative to serving each callincludes the step of comparing the zone of the floor call and the zoneof each car.
 21. The method of claim 16 including the step of providingmeans in each elevator car for passengers to register car calls, andwherein the step of deleting a floor call allocation from the assignmentregister of an elevator car when a closer suitable car is found issubject to the condition that the car has no registered car calls. 22.The method of claim 16 including the step of providing a signal when adown floor call is allocated to the assignment resister of an elevatorcar, which signal is considereD during the step of considering thesuitability of the car for another down floor call, removing this carfrom consideration for such a call.
 23. The method of claim 16 whereinthe step of successively considering at least certain of the elevatorcars relative to serving each call in the ordered call table considersthose elevator cars which are not in the process of serving a call forelevator service as not suitable for allocation of calls, and includingthe step of assigning elevator cars in this category to floor calls forwhich a demand signal was created by the processing step.
 24. Anelevator system for a structure having a plurality of vertically spacedfloors, comprising: a plurality of elevator cars, means mounting theelevator cars for movement relative to the structure to serve thefloors, down floor call registering means operable for registering acall for elevator service in the down direction from each of a pluralityof said floors, up floor call registering means operable for registeringa call for elevator service in the up direction from each of a pluralityof said floors, car call registering means for each of the elevator carsoperable for registering a call for each of a plurality of said floorswhich may be desired by load in the associated elevator car, dispatchingmeans for allocating registered floor calls to selected elevator cars,and assignment register means associated with each of said elevator carsoperable to receive floor call allocations from said dispatching means,said dispatching means including: first means for collecting floor callsfrom said up and down floor call registering means, second means forperiodically ordering the floor calls collected by said first means suchthat their locations relative to one another correspond to the locationsof their associated floors in the structure, said first means addingfloor calls collected subsequent to the ordering of the floor calls bysaid second means to an end of the ordered floor calls, and third meansfor periodically processing certain floor calls collected by said firstmeans by either allocating a selected floor call to the assignmentregister of at least one elevator car or registering a demand signalrelative to the call, said third means being responsive to said secondmeans, processing all of the floor calls each time said second meansorders the floor calls and otherwise only processing floor calls addedto an end of the ordered floor calls, said third means, when processinga floor call previously allocated to an elevator car, allocating thefloor call to a second car in response to predetermined conditions anddeleting this floor call allocation from the assignment register of thefirst car in response to a predetermined condition.
 25. The elevatorsystem of claim 24 including control means responsive to predeterminedconditions the occurrence of any one of which indicates a possible needto reallocate at least certain of the floor calls, said control meansbeing in a first condition in the absence of all of said predeterminedconditions and in a second condition when any one of said predeterminedconditions occur, wherein the dispatching means is responsive to saidcontrol means, with its second means being effective when said controlmeans is in its second condition to order all of the floor calls, andcause its third means to process all of the floor calls, and with thethird means processing only the calls at the end of the ordered floorcalls when the control means is in its first condition.
 26. The elevatorsystem of claim 25 wherein the predetermined conditions to which thecontrol means is responsive includes an elevator car bypassing floorcalls and an in-service elevator car going out of service.
 27. Theelevator system of claim 24 wherein the predetermined conditions towhich the third means will allocate a floor call previously allocated toa first car to a second car include the secoNd car being locatedrelative to the call floor and with a service direction consistent withthe service direction of the call, and with an advanced car positionwhich is closer to the call floor than the advanced car position of thefirst car.
 28. The elevator system of claim 24 wherein a predeterminedcondition which will cause the third means to delete a call allocationfrom the assignment register means of a first car after allocating thefloor call to a second car is the absence of a car call on the car callregistering means of the first car.
 29. The elevator system of claim 24wherein the third means includes means for excluding cars not in theprocess of serving a call for elevator service from consideration whenallocating floor calls, and including means for assigning cars in thiscategory to floor calls for which a demand signal was registered by thethird means, and wherein said third means successively compares each carhaving an advanced car position and service direction suitable to answera specific call with a previous car found suitable to determine whichcar has an advanced car position closer to the floor of the call, anduses the closer of the two for any subsequent comparison, to obtain theclosest suitable car to the call floor when all cars have beenconsidered, with said third means allocating the call to the assignmentregister means of the closer suitable car.
 30. The elevator system ofclaim 24 including means for excluding an elevator car fromconsideration as being suitable for allocating a down floor call when italready has a down floor call in its assignment register means.